1. Field of the Invention
The present invention relates generally to self-propelled irrigation systems, and more particularly, to an improved drive wheel assembly for a self-propelled irrigation system.
2. Description of the Prior Art
Self-propelled irrigation systems are used to provide water for agricultural purposes in arid regions. Typically, such systems include a series of spaced drive towers connected by truss sections that support a water distribution pipeline between the towers. In center pivot systems, the water distribution pipeline extends radially from a central pivot connected to a water supply. In linear move irrigation systems, the water distribution pipeline extends laterally from a canal feed or hose drag system that provides the water supply.
Water passing through the distribution pipeline is forced out through a number of sprinkler heads, spray guns, drop nozzles, or the like spaced along the length of the pipeline. Each drive tower in the system is supported on wheels that are driven at slow speeds to move the tower in a circular path about the central pivot, or a linear path in the case of linear move systems, to thereby irrigate a large tract of land.
Conventional drive towers for self-propelled irrigation systems are each supported by a base beam that extends transverse to the distribution pipeline with a drive wheel assembly at each end of the base beam. The drive wheel assemblies typically include a metal wheel rim with a rubber tire with lug tread mounted on the wheel rim. The weight of the drive tower and the corresponding part of the water pipeline is approximately evenly distributed between the two drive wheel assemblies. However, in difficult terrain drive towers sometimes become stuck or leave deep ruts in the field, which are undesirable.
There have been many attempts in the prior art to improve the flotation and traction of drive wheels used with self-propelled irrigation systems. For example, U.S. Pat. No. 7,775,610 issued to Mettenbrink discloses a flotation drive wheel that has a plurality of pivotal flotation shoes attached to a heavy metal hub portion. However, Mettenbrink's wheel is expensive to manufacture, cannot be mounted as an attachment to existing wheel rims, and does not allow convenient replacement of wear parts.
There is a need in the industry for an improved drive wheel assembly for self-propelled irrigation systems.